In ambulances and other emergency/rescue vehicles, removable, wheeled cots or stretchers are often provided for convenient and comfortable patient transportation from a remote accident site to the emergency vehicle. These cots or stretchers are often referred to as "roll-in" devices, and generally feature a plurality of wheels for inserting and removing the cot from the emergency vehicle, as well as an adjustable or multi-level fold down carriage supporting a set of wheels which enables the cot to be easily rolled along sidewalks, roads, or other access surfaces.
The mobile patient transportation cots or similar devices commonly include a structural frame, which is often tubular in nature, to provide lightweight support for the patient and the wheels, casters or other rolling mechanisms attached thereto. Once the patient is rolled to the emergency vehicle on the cot, the undercarriage may be collapsed and folded under the cot to facilitate insertion of the cot into the emergency vehicle. The cot is then rolled into the emergency vehicle and fastened into position for safe transportation.
A cot fastener system comprising a front member often referred to as an "antler" bracket, and a rear fastening rail has been widely used in the industry for a number of years. Particularly, the front bracket generally includes a pair of upwardly . extending hook-like members which curve to the rear of the emergency vehicle and are designed to receive and effectively hook onto portions of the forward support frame members of the cot. This bracket thereby limits forward movement of the cot within the emergency vehicle. A separate rear fastening rail is thereafter secured to the cot frame to secure the cot against further rolling movement within the emergency vehicle.
While such cot fastener systems have been widely and successfully used, there are a plurality of designs for cots and other wheeled devices utilized in various emergency vehicles and the like, and interchangeable use of prior cot fastener systems often required modification of the fastener system itself or its installation, or adjustments to the system. A fastener system which could accommodate a broad range of cot models and which could automatically and dependably accept and function properly with those various models without modifications or adjustments has heretofore been unavailable in the industry.
Some cot fastener systems which function in the manner described above also feature only limited abilities to maintain the secure position of the wheeled device when subjected to violent jarring and/or impact forces sometimes encountered in use, such as sudden lurches, stops, collision impacts or rollovers. Such hazards are encountered, for example, by ambulances or other emergency vehicles with varying degrees of frequency. It has been found that some prior cot fastener systems do not prevent a "secured" cot from extending away from the floor of an ambulance during rollover accidents as a result of the folded under-carriage unfolding and/or the antler bracket or rear fastener rail being unable to support the sudden stresses exerted in such a situation.
Similarly, while the cot fastener systems are often well designed to resist forces tending to urge the cot in a forward direction during sudden stops and the like, such systems are often unable to maintain the cot in secured position when the vehicle is subjected to a sudden force from behind, such as a rear-end collision. As can be understood, in situations where the cot and its fastener systems are subjected to sudden impact force, it is clear that any inability of the fastener system to maintain the cot in a secure fashion can endanger the health and well being of any patient riding on the cot and other persons and property surrounding the cot both within and without the emergency vehicle. An unsecure cot could obviously injure other passengers within the vehicle or, in some cases, be thrown from the vehicle injuring property or persons outside of the vehicle.
Consequently, while there have been available cot fastener systems which can be adapted to function well with the wide variety of cots commonly utilized in the industry, there has heretofore not been available a single fastener system which provides automatic adaptability to a plurality of commonly encountered cot models, and can also provide enhanced securement characteristics for withstanding the assortment of forces and stresses imposed on a fastener system used in dynamic applications such as emergency vehicle and rescue squad applications.